1. Technical Field
The present disclosure relates generally to medical/surgical ablation, devices, assemblies and methods of their use. More particularly, the present disclosure relates to cooled microwave antenna assemblies comprising a helical antenna configured for direct insertion into tissue for diagnosis and treatment of the tissue and methods of using the same.
2. Background of Related Art
In the treatment of diseases such as cancer, certain types of cancer cells have been found to denature at elevated temperatures (which are slightly lower than temperatures normally injurious to healthy cells). These types of treatments, known generally as hyperthermia therapy, typically utilize electromagnetic radiation to heat diseased cells to temperatures above 41° C. while maintaining adjacent healthy cells at lower temperatures where irreversible cell destruction will not occur. Other procedures utilizing electromagnetic radiation to heat tissue also include ablation and coagulation of the tissue. Such microwave ablation procedures, e.g., such as those performed for menorrhagia, are typically done to ablate and coagulate the targeted tissue to denature or kill it. Many procedures and types of devices utilizing electromagnetic radiation therapy are known in the art. Such microwave therapy is typically used in the treatment of tissue and organs such as the prostate, heart, and liver.
One non-invasive procedure generally involves the treatment of tissue (e.g., a tumor) underlying the skin via the use of microwave energy. The microwave energy is able to non-invasively penetrate the skin to reach the underlying tissue. However, this non-invasive procedure may result in the unwanted heating of healthy tissue. Thus, the non-invasive use of microwave energy requires a great deal of control. This is partly why a more direct and precise method of applying microwave radiation has been sought.
Presently, there are several types of microwave probes in use, e.g., monopole, dipole, and helical. One type is a monopole antenna probe, which consists of a single, elongated microwave conductor exposed at the end of the probe. The probe is sometimes surrounded by a dielectric sleeve. The second type of microwave probe commonly used is a dipole antenna, which consists of a coaxial construction having an inner conductor and an outer conductor with a dielectric separating a portion of the inner conductor and a portion of the outer conductor. The third type of microwave probe commonly used is a helical antenna. Helical antennas are typically composed of a single driven element, or conducting wire, coiled in a spiral, or helix. In the monopole and dipole antenna probe, microwave energy generally radiates perpendicularly from the axis of the conductor. Helical antenna may radiate in a normal mode, in which the radiation pattern is similar to that of an electrically short dipole or monopole or the helical antenna may radiate in the axial mode, in which the radiation pattern is circular.